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A porous microplate embedded with two nanocomposite piezoelectric layers is investigated in the current work. All three layers are functionally graded and completely attached to each other, and the microstructure lies on a bi-parameter elastic foundation that withstands shear and normal forces simultaneously. Also, an external voltage is subjected to the piezoelectric patches. The mentioned patches are reinforced with carbon nanotubes to enhance their electro-mechanical performance. A higher-order shear deformation theory and von Karman's assumptions are hired to demonstrate the kinematic relations. Next, applying Hamilton's principle and variational technique, the governing motion equations are derived with the help of the modified couple stress theory to capture the scale influence. To solve the system of differential equations, a closed-form Navier method is employed, and by ensuring the correctness of the results, then it turns to investigate the impact of different factors including porosity percentage and also pores' distribution patterns, nanotubes dispersion patterns, and other important factors on the natural frequencies of the model. Obtained results show that symmetric and uniform porosity distributions have the maximum and minimum amounts of natural frequencies. Moreover, the maximum difference between natural frequencies of three different porosity distribution occurs in e0 = 0.95 and is approximately 32%. The current study results may consider to design and produce smart structures and devices with improved performance. [ABSTRACT FROM AUTHOR]

Present study deals with the nonlinear analysis of thermally induced deflection and snap-through buckling in functionally graded porous (FGP) curved nanotubes. It is assumed that the curved nanotube is rested on a two-parameter nonlinear elastic foundation. The curved nanotube is subjected to uniformly distributed transverse pressure loading and also uniform temperature rise. Distribution of thermomechanical properties in the thickness of curved nanotubes is radially graded according to a power law function. The even type of porosity distribution patterns is included into the formulation and all properties are considered as temperature dependent. The nonlocal strain gradient and uncoupled thermoelasticity theories are provided to analyze the geometrically nonlinear behaviors of curved nanotubes. The equilibrium equations are obtained based on the high-order shear deformation theory. To capture the large deformations, the von Kármán type of nonlinear kinematic assumptions is included. Two types of immovable boundary conditions are considered which are simply-supported and clamped-clamped. The equilibrium equations are reformulated and transferred into the dimensionless presentation. The closed-form expressions are provided to trace the thermal/mechanical load-deflection paths of curved nanotubes using the two-step perturbation technique. Numerical results of this study are compared with the available data in the literature for the macro-scale curved tubes. After that novel parametric results are provided to discuss the effects of nonlocal and length scale parameters, boundary conditions, porosity coefficient, foundation stiffness, power law exponent, and geometrical parameters. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the mechanism of sustainable biodegradation of long-alkanes with moderate pre-oxidation in soil. Moderate pre-oxidation was performed with two consecutive doses of 1.35 mL 30% of H2O2 (225 mM) in two soil. After moderate pre-oxidation, the experiment of sustainable biodegradation of long-alkanes during 80 d was conducted. Then, long-alkanes relative activity coefficient (K), NH4+-N allocation (G) and the performance of hydrocarbon degraders (E) was calculated. Long-alkanes were sustainably biodegraded with moderate pre-oxidation (1765 mg/kg, 2438 mg/kg and 2672 mg/kg). Long-alkanes biodegradation (8723 mg/kg) with moderate pre-oxidation was 2.5 folds of excessive pre-oxidation. The average increment in long-alkanes biodegradation with moderate pre-oxidation was 30–38% as K values improved (0.28–0.48). The bacterial destruction D decreased to 14–17% and hydrocarbon degraders activity increased to 0.065 mol CO2/kg with moderate pre-oxidation. Basidiomycota and Acinetobacter sp. showed high tolerance with moderate pre-oxidation and remained dominant strains throughout the bioremediation. NH4+-N consumption played an essential role as nutrients in growth of hydrocarbon degraders (Basidiomycota and Acinetobacter sp.). Then, high and sustained E was achieved with decreased D and elevated hydrocarbon degraders activity, resulting in high K. So, long-alkanes sustainably increasing biodegraded under high E assisted with elevated G with moderate pre-oxidation. [ABSTRACT FROM AUTHOR]

In this study a new photocatalytic nanocomposite, S-g-C 3 N 4 /MgAl-CLDH, was synthesized and implemented into cement mortar by internal mixing or coating. The photocatalytic NO x degradation efficiency of the S-g-C 3 N 4 /MgAl-CLDH and photocatalytic mortar was investigated. The NO x degradation efficiency and photoluminescence spectra of S-g-C 3 N 4 /MgAl-CLDH after being immersed in the simulated concrete pore solution were evaluated to assess its chemical stability. The results show that compared with S-g-C 3 N 4 , the S-g-C 3 N 4 /MgAl-CLDH exhibits a narrower bandgap (2.45 eV), a lower photogenerated electron-hole pair recombination rate and a higher specific surface area (36.86 m 2 g -1 ). After 21 min of visible light irradiation, the NO x degradation rate of S-g-C 3 N 4 /MgAl-CLDH achieves 100% as compared to merely 81.5% of S-g-C 3 N 4 . After being submerged in simulated concrete pore solution, the S-g-C 3 N 4 /MgAl-CLDH exhibits only a slight decrease of 5% in degradation rate after 12 min of irradiation, confirming a good compatibility and stability in cement-based materials. The NO x degradation ability of the internally mixed mortar is enhanced with an increase in the dosage of S-g-C 3 N 4 /MgAl-CLDH. For coated mortar, in contrast, a decline in NO x degradation rate is observed after 5 layers of coating owing to the lower porosity of mortar after excessive coating., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)